rain

[AggrorJorn]

Well you could make a predefined particle which you call rain. you can drag it into the scene and start making areas where it is needed. That is as handy as an the matrix you suggested but for many people it will just do the trick.

Simply said you don't place the particle where the rain should be. However if there was some table outside, you would have to be more precise placing particles. yet if the table moves, the particles are no longer correct. But you would have that problem to, if you would use a pre-calculated matrix.

[Chris Paulson]

This is an untested idea which is complicated but might work.

 

1) Place camera high (some height depending on grid resolution needed) in sky pointing at ground. Place camera in orthogonal view mode?

 

2) Render scene to texture/buffer

 

3) Process depth buffer - this giving you a height map grid (not sure how this is done - this is the tricky bit)

 

4) Set rain emitters to only fall distance from camera height to height in height map grid

[flachdrache]

Or do it the other way around -

 

.pick random surfaces in camera view

.if it hits the skybox/skysphere while shooting up

.allow a raindrop fall at that target pos

.if raindrop is done spawn a decal at picket target

 

could be any surface even npcs ( ignoring different worlds atm though ).

with a "solid" system this could be used for ricochets, lightning strikes etc.

 

[edit] ... n/a

[Rick]

I'm willing to bet any sort of raycast system will be very very slow.

[irishlostboy]

i made this an age ago in doom3.

using two particle systems. i do wish games did better rain. rain is so atmospheric. i love rain. good job i live in ireland, where it never stops.

i look forward to seeing what conclusions are found by you guys trying to develop rain.

[AggrorJorn]

That was some nice rain irishlostboy. I found a vertex shader on my harddrive that is called rainpart.vert. Some community member gave it to me once but I enver used it. It doesn't work right away but perhaps I can get it going. Let you guys know